That topic is very old. The modern approach is to include a SystemD override with AmbientCapabilities=CAP_NET_BIND_SERVICE. Or similar for Docker. See these topics:
Also, consider using a systemd override file instead of editing the main file, e.g.:
systemctl edit Ignition-Gateway.service
This will create an override file at /etc/systemd/system/Ignition-Gateway.service.d/override.conf that will persist through an Ignition upgrade (that may reset/revert that base configuration file).
Greetings! I wanted to announce that the container image for the next nightly (which will eventually end up in the 8.1.26 release) contains changes to the default user/group that is used to launch Ignition.
The default user is now ignition with UID/GID of 2003. You'll have to perform a migration in order to successfully transition your existing data volumes, otherwise you may encounter an error such as this one below:
init | 2023/02/13 11:50:21 | Creating init.properties file
init | …